A Reverse Conduction Insulated Gate Bipolar Transistor

Abstract

A reverse conduction type insulated gate bipolar transistor, the invention relates to power semiconductor devices, aiming at the problems existing in RC-IGBT devices in the prior art, the invention provides a design scheme: by optimizing the backside n of the RC-IGBT device + The distribution of the cathode region can solve the problems existing in the prior art. Compared with the traditional RC-IGBT device, the RC-IGBT device of the present invention can maintain a lower positive direction of the device through the special design of the back structure. On the basis of suppressing the turn-on voltage rebound problem of the device without increasing the reverse conduction loss and the process cost, it is beneficial to improve the reliability of the RC-IGBT in practical applications.

Description

technical field [0001] The invention relates to a power semiconductor device, especially the structural design of a reverse conduction insulated gate bipolar transistor (RC-IGBT), that is, a reverse conduction insulated gate bipolar transistor. Background technique [0002] Insulated gate bipolar transistors (IGBTs) are key semiconductor components in electronic systems and are widely used in various medium and high voltage power control systems, such as motor drives and power conversion. An IGBT device contains three electrodes: a collector, an emitter, and a gate that controls the switching of the device. Generally, when the gate is turned off, the traditional IGBT is equivalent to a PNP transistor with an open base, so it does not have the capability of reverse current flow. As a result, the traditional IGBT can only be used as a unidirectional conduction device, that is, the current can only flow from collector to emitter. However, most power circuit systems have the r...

AI Technical Summary

Problems solved by technology

This turn-on voltage foldback phenomenon has a huge negative impact on the reliability of RC-IGBT applications

For example, for multiple parallel-connected RC-IGBTs or RC-IGBTs with a large chip area, due to the deviation of chip processing technology, the The voltage return point of the chip is often not consistent, which leads to the current concentrated flow to a single chip or a certain local area of ​​a single large chip, causing the chip to be burned due to excessive current

[0006] In order to avoid the turn-on voltage foldback phenomenon, it is necessary to enable the PN junction between the p-type collector layer 106 and the n-type field stop layer 105 of the RC-IGBT to be opened under the lowest possible forward voltage drop of the device. Common methods include: (a) increasing n - The doping concentration of the drift region 101 or reduce n - The thickness of the drift region 101 to reduce n - The resistance of the drift region, but this method will reduce the breakdown voltage of the device; (b) reduce the doping concentration or thickness of the n-type field stop layer 105, and increase the resistance of the n-type field stop layer 105 on the electron current path, so as to increase p + The potential difference of the PN junction between the collector region 106 and the n-type field stop layer 105 enables the above-mentioned PN junction to be opened at a lower electron current, but this method also reduces the breakdown voltage of the device; (c) Extend the current path length of electrons in the n-type field stop layer 105, that is, increase the adjacent n + The interval of the cathode region 107 can also improve the resistance of the n-type field stop layer 105 on the electron current path, increasing the p + The potential difference of the PN junction between the collector region 106 and the n-type field stop layer 105, but this method will aggravate the inhomogeneity of the current distribution inside the device and increase the forward conduction loss of the device

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